Metalworking machine



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W www ATTORNEY M. S. CURTIS METALWGRKING MACHINE April 7, 1936.

Filed Aug. 26, 195o 4 Sheets-Sheet 4 ATTORNEY Patented Apr. 7,I 1936 UNITED STATES 2,036,260 METALWORKING MACHINE Myron S. Curtis, Pawtucket, R. l., assigner to William Wallace Potter, Pawtucket, lt. I. Application August-36, 1930, Serial No. 477,832

Claims. (Cl. Z9-4d) My invention comprises gearing for metal working machines which have an element for holding work and a second element for holding tools to operate on the work, one of these elements being t rotatable, and the elements being capable of being moved towards and from each other for the purpose of presenting the tools to the work,` and removing them from the work.

As one embodiment of my invention, I have selo lected alturret lathe, which the work-holding element (a spindle) revolves, and the tool-carrying element (a slide) is moved towards and from the work-carrying element. It is, however, understood that I do not limit myself to this particular l5 embodiment nor to an embodiment in which the tool holder moves, and the work-holder revolves,

i or the Work-holding element might be stationary,

and the tool-holding element rotatable; the

work-holdingy element might be movable towards 20 and from the tool-holding element; or, they might both be movable; or, there might be any combination thereof. y

In the turret lathe selected, it is desirable that the work-holding element, orgyspindle, be revolv-` p 2% able pat different speeds automatically selected and that entirely different sets of automatic speed changes may be secured, as by means of hand change gears; that the feedA of the tool holdingelement or tool slide be maintained in permanent 0 ratio with the spindle while the tools are in a position to do work; that the tool slide have both automatic and hand changes'of speed, and that it have for its idle, or non-working movements a constant speed, fast motion entirely independent ma of and unaffected by the speed of the work holding element or spindle; and'that there be a single constant speed driving element from which spindle and tool slide movements are derived.

no It is also desirable that the power connection.y

between the constant speed driving-element and the spindle and between spindle and tool slide be changes capable of extremely small or gradual -compared with stepped` changes, to cover the w whole range of speeds of the machine, and yet be positive (in contradistinction to frictional) and be automatically controlled. For this purposeI provide a speed change unit capable olfv gradual or progressive variation of speeds contrasted with stepped changes as in ordinary gear trains, which includes driving and driven pulleys and a belt between them,` which have a toothed connection, but I do not limit myself to this particular type t a ot speed change unit. An important feature oi my invention is my means for accomplishing the described variations in the speed.

My invention consists in whatever is described by or is included within the terms or scope ot the appended claims.

Referring to the drawings:

Fig. l is a front elevation of the automatic turret lathe, selected to illustrate an embodiment oi my invention;

Fig. 2 is a vertical cross section substantially W on the line l2, of Fig. l;

Fig. 3 is a-cross section through substantially the line 3-3 of Fig. 2 with the shaft that gears the speed change unit and the spindle shown displaced for clarity of illustration;

Fig. 4 is a rear elevation;

Fig. 5 is a cross section through the feed gearing of the machine with the shafts shown out of their actual position in the machine, for clarity or illustration; 2@

Fig.` 6 is a cross sectionthrough one of' the control units;

Fig. '7 is an end elevation of Fig. 6;

Fig. 8 is a side view of the lever actuated by 25 the dog drum, that controls the operation of the speed change unit.

The machine shown in the drawings has a base, lil, which at the top has a housing lli, for the spindle i2, provided as usual with the work-holding chuck, i3. The spindle rotates in. bearings i4 and l5 in the housing I l, and keyed to it near one end is a gear, it, with which pinionll keyed to shaft ld meshes. Removably keyed to the other end of vshaft i8 is change gear lwhich meshes with change gear 2U; also removably keyed to shaft 2 l 0n shaft 2i are keyed opposing gear cones 22 and 23 that are slidable towards and from oneanother which by a gear-faced chain 28, is positively geared to and positively driven ,w

from gear cones 25 and 26. Gear cones 25 and 26 are slidably keyed to shaft 2li.Y These gear cones or, each of the two pairs 23 may be moved toward and from each other by means of arms, 2B, and 29, pivoted on studs 30 and 3|, respective- ,w

. ly, by means hereinafter described and' these gear cones, together with theconnecting chain and the operating arms, constitute the essential features of the positive speed change unit I prefer to use. as the arms 28 and 29 are pivoted bef- 5@ tween their cone-engaging ends, it will be seen, as gear cones it and 26 are forced together, gear cones 22 and it will, at the same time, be forced apart. and vice versa. and the chain 2t will change its radial position respectively tothe two sets oi pp slidably mounted on 16 to which tools may be fastened and which mayY cones and therefore change the speed ratio between shafts 21 and 2|, and this change may be made by gradual or progressive graduation and thus the nicest and widest variation in spindle speed may be obtained.

Shaft 21 has keyed to it, gear 32 which meshes With gear 33, keyed to constant speed shaft 34, which is driven from some outside source by pulley 35. Through gear connections described with shaft 34, spindle I3 is driven from constant speed shaft 34 with an automatic gradual compared with stepped variation of speeds through the positive speed change unit and a hand variation of speeds through the change gears I9 and 20.

Power to drive the tool slide feed shaft for,

working feed of the tools is taken from spindle, I3. For this purpose keyed to spindle I3 is sprocket, 36 that by chain 31, drives sprocket 38, keyed to shaft 39. Slidably keyed to shaft 39 are gear cones 40 and 4|, of another positive speed change unit which drive cones 42 and 43 slidably keyed to shaft 44 through gear chain 45, the four cones being controlled in position, by levers 46 and 41 pivoted on studs 48 and 49 respectively. Removably keyed to shaft 44, is change gear 440 which meshes with change gear 44| removably keyed to jackshaft 442, to the other end of which is keyed gear 443 meshing with ratchet gear 444 on feed shaft 58, which shaft transmits motion to the cam drum for reciprocating the tool slide. Ratchet gear 444 may drive shaft 50, or shaft 50 may run away from gear 444 when driven at a higher speed through clutch 5I, keyed to shaft 50, clutch gear 52 freely revolving on shaft 50 and driven by pinion 53 keyed to shaft 54. Shaft 54 is driven at a high constant speed from .pulley shaft 34 through pulley, 55, belt 56 and pulley 51. Therefore, when clutch gear 52 is connected with clutch 5|, feed shaft 50 is driven at a high speed and runs away from ratchet gear 444, and when clutch gear 52 is disconnected from clutch 5|, shaft 50 is picked up and revolved by ratchet gear 444m a well known manner. Thus feed shaft 50 may be driven from the spindle at a slow speed for work, which, though automatically variable is in xed ratio to the spindle speed, or it may be driven at a high, constant speed driven from constant speed shaft 34, for the retwtn and other idle motions of the tool slide.

Slidably keyed to shaft 59, is friction clutch head 58, which can be clutched or declutched with friction cone 59, keyed to shaft 60, and thus, shaft 6U can either be driven by feed shaft at its various speeds, or it may be entirely disconnected.

Shaft 66, through bevel gears 6| and 62, drives worm shaft 63, to which is keyed worm 64 which by means of worm gear 65 revolves cam drum 66. The drum by means of cam path 61 and cam roll 68, fast to turret slide 69, moves the latter toward and from the chuck, I3. Turret slide 69 is base I0 andv carries turret be indexed as usual, by means which do not form part of this invention.

Various other tool carrying slides such as a cross slide 1| may be mounted on the base I6 and driven from feed shaft 5|) by suitable gear connections not necessary to describe.

Feed shaft 66, also, by means of bevel gears 12 and 13, worm shaft 14, worm 15 and worm gear 16, drives dog drum 11 at such a speed that there is one revolution of dog drum 11 for each complete cycle of the machine; and the various automatic operations of the machine are controlled by dogs on drum 11. The front end of shaft 14 may be squared to receive a crank handle and thus the various slides may be operated by hand when clutch 58 is disconnected from cone 59.

'I'he operation of clutch 58 is automatically accomplished by dog 18, adjustably fastened to drum 11, through lever 19, shaft 80, lever 8|, connecting-rod 82, link 83, and clutch yoke 84, or may be manually operated through hand lever which is an integral part of lever 19. Clutch 52 which controls the fast and slow feed is operated by dogs, 88, adiustably mounted on drum 11, through lever 81, shaft 88, lever 89. connecting-rod 9|l, link 9| and clutch yoke, 92, or may be manually operated by hand lever 93 which is an integral part of lever 81.

The cone gears of the positive speed change units are automatically or manually controlled to change spindle speed and tool speeds by hydraulic mechanism and as the one which operates the spindle, and the one which operates the feed, are identical in construction and operation, the former only will be described.

As has been before stated, the speed variation is accomplished by sliding the cones of each pair towards and from one another by means of levers 28 and 29. Movement of these levers is accomplished by pistons 94 and 95 (see Fig. 6). These are mounted at opposite ends of a common piston rod 96 and which at midlength has pinned to it a collar 91 with a ridial arm 98 (see Fig. 7) to which is attached connecting-rod 99 (see Fig. 2) pivoted at one end to lever |90, pivoted near its middle at IUI. lThe other end of lever, |08, by means of knuckle block, |92, and toggles |03 and |94 is connected to and operates coneshifting arms 2f! and 29. Collar 96, has another arm |05 (see Fig. 6) pinned to it and when the pistons move, operates slide valve |01 which con trols ports |08 and |89 in cylinder block IIO of pistons 94 and 95 and which also coacts with ports in slide valve Valve ||I is reciprocable by rotary cam ||2, through pin II3, engaging the cam groove, on a rod I|4, extending from valve III, (Fig. 2).

Cam ||2 is oscillated to shift the slide valve III, by dog, H5, adjustably fastened to dog drum 11 and which, by means of cam face, IIS, which coacts with pin I|1 oscillates lever I I8 in a direction parallel to the axis of the dog drum. Lever ||8 is fastened to collar ||9 by pivot screws |20, and collar 9 is fastened to one end of shaft |2I, to the other end of which is fastened cam, H2, so that when lever ||8 is oscillated in a direction parallel to the axis of the dog drum by dog H5, cam ||2 is also oscillated and shifts `valve III.

plunger I 24 closes drain valve |26, but when lever I8 is oscillated by cam |22, valve plunger |24 is pushed in against the pressure of spring |23, and thus opens drain valve |26. The functions of this drain valve will be hereinafter described.

The cylinders of pistons 94 and 95 in cylinder block are supplied with iiuid under pressure by pump |21 (Fig. 2) which is driven by shaft 34 through gears |28 and |29. The pump sucks fluid through pipe |30 from sump |3| and delivers it through pipes |32 to port |33 in cylinder block ||0, the desired pressure being maintained by means of relief valve |34 in the pump delivery line. Fluid under pressure passes from port |33 to cylinder |35 of piston 94 through port |36 and to cylinder |31 of piston 95, through port |38 so that an equal pressure is normally exerted upon pistons 94 and 95, thus balancing them so that no movement may take place. Cylinder |35 may be connected with drain valve |26 through port |08, port |39 in slide valve |01, port |40 in slide valve ports |4|, |42 and |43 and pipes |44, and cylinder |31 may be connected with drain valve |26 through port |09, port |45 in slide valve |01, port |46 in slide valve III, ports |41, |42 and |43, and pipesv` |44. These connections are normally closed by slide valves and |01 as illustrated in Fig. 6, where the pistons 94 and 95 are also shown in their extreme left hand position.

Valve may now be moved to the right by partial rotation of cam ||2, and port |46 will be immediately uncovered and cylinder |31 connec`ted with the drain valve |26. If drain valve |26 is closed, no movement will take place, but immediately that it is opened, a free passage will exist from cylinder |31 through to the drain and the pressure in cylinder |31 will drop.' The excess of pressure in cylinder |35 will now cause the pistons to move to them slide valvel |01 and they will continue this movement until slide valve |01 closes port |46,

when a condition of equilibrium will be again established, and motion will stop. In other words, when drain valve |26 is open, pistons 94 and 95 will be caused to move so that valve, |01, always follows valve In the same way, the pistons may be movedA toward the left, by a movement of valve V|||l to the left uncovering port |40. It is, therefore, apparent that slide valve may be placed in any desired position by means of camv I6 on dog |`I5 while valve |26 is closed, then valve |26 may be opened by cam l|22 on dog ||5 and pistons 94 and 95 will immediately move until valve |01 has` closed the ports in valve Or, if desired, drain valve |26 may be first opened by cam |22 before cam ||6 positions valve In this case, movement of the pistons will start immediately, when cam ||6 starts to swing lever IIB, and will continue until lever ||8 comes to rest or until valve |26 is closed. From this I secure the following advantages: First, slide valve may be set to its desired position and then by opening drain valve |26 a quick change'from one speedto another will` follow. This is desirable when turning tools are working on the shoulders of different diameters. Second, by first opening drain valve |26 and then slowly positioning valve a slow, progressive change of speeds will follow. This is desirable when facing a piece of work. These speed changes may also be accomplished by hand through hand lever |41 which is an integral part of lever H8, and the feed changes are similarly accomplishedv by dogs |48 acting on lever |49, or manually by hand lever |50 which is an integral part of lever |49.

An important advantage of my double piston arrangement is that no piston rod packing is rethe-right, carrying with quired; and l also require no packing for the slide valves.

l. A machine tool having cooperating work and tool holders, one being a rotating spindle, and the'other a slide, a positivetype variable speed connection between said rotating spindle and the slide, that includes adjustable means, to transmit motion at gradually changeable speeds between its minimum and maximum limits, a movable control member, operating means between such control member and said adjustable motion transmitting means, and an operating connection between said spindle and said control member.

-2. A machine tool, as in claim 1, in which there is a drive shaft and a positive type variable speed connection between said shaft and the spindle, and operating means between such variable speed connection and the control member for changing speed of such connection.

3. A machine tool, having cooperating work and tool holders, means for rotating the work holder, means to impart relative motion of approachA and withdrawal to said work and tool holders, comprising a speed changing unit with positive motion transmitting means, adjustable to transmit motion to said holder at gradually changeable speeds between its minimum and maximum limits, a rotatable control member, a

driving connection between vthe work holder rotating meansand said control member, and an `operative connection between said control member and the adjustable element of s'aid positive motion transmitting means.

4. A machine tool', as in claim 3, in which the positive motion transmitting means includes two sets of opposite cones, a shaft on which each set is mounted and on which opposing cones are shiftable toward and from one another, and a belt between the cones of the two sets, cone faces and belt edges having a positive cooperating driving surface, and having means to shift the cones of both sets simultaneously controlled by said control member.

5. A machine tool, comprising a revolving work spindle, and a reciprocating tool slide thathave cooperative relation, a variable speed power transmitting unit having driving and driven members, that are adjustable, for changing the speed -ratio between said driving and driven members, a movable control element,.an operative connection between said control .element and said adjustable members, that includes means for preyselecting a desired speed and for then changing the speed, and means for immediately changing the speed independently of the pre-selecting means, and a driving connection between the spindle and said control element.

6. A machine tool, comprising rotatable work and slidable tool holders, means to impart motion to at least one of such holders, comprising a speed changing unit adapted to transmit motion to said holder at gradually changeable speeds between minimum and .maximum limits, said speed-changing means including oppositely situated, spaced apart driving and driven rotary elements, motion transmitting means interposed between such elements, in motion transmitting engagement, with both, slippage control means that control slippage between the engaging surfaces of said elements and said motion transmitting means, a movable control element, an operativ connection between said slide and said control member.

8. A machine tool having cooperating Work and tool holders, one being a rotating spindle, and the other a slide, a positive type variable speed connection between said rotating spindle and the slide that includes adjustable means to transmit motion at gradually changeable speeds between its minimum and maximum limits, a movable member and said adjustable motion transmitting means, and operative-connections between said control member and said slide and said spindle.

MYRON S. CURTIS. 

